Change speed gear



Oct. 26, 1937. MJWAGYNER 2,095,770

CHANGE SPEED GEAR Filed Dec. 26, 19:54 2 Sheeis-Sheetl Oct. 26, 1937.

'. M. WAGNER CHANGE SPEED GEAR Filed Dec. 26, 1 54 -2 Sheets-Sheet 2' 35 the higher to the lower Patented Oct. 26, 1937 UNITED. STATES QHAN GE SPEED GEAR Max Wagner,

Stuttgart, Germany, assignor, to

Daimler-Benz Aktiengesellschaft, Stuttgart- Unterturkheim, Germany Application December 26, 1934, Serial No. 759,303 In'Germany December 27, 1933 10 Claims.

This invention relates to a change speed gear and has for its main object to make the gear changing operation considerably easier and the gear practically noiseless. The invention furtherv relates to a particularly suitable construction and arrangement of the means for facilitating the change of gear and of the whole gear itself.

Gears with several noiseless speeds are for instance known, in which the speeds are formed by 10 three pairs of toothed wheels which are always in mesh and are operated by means of two changeover clutches which are provided with dogs having inclined end surfaces and are changed over without a middle position of rest. This arrange- 15 ment can, however, not be used in all cases, since,

when both change-over clutches are operated simultaneously the re-engagement of the dogs which are inclined on one side may in some circumstances cause difficulties, For this reason auxiliary clutches have already been proposed,

" by means of which the-disengaged parts of the gear can be reconnected with the engine or the vehicle. 7

The invention overcomes this disadvantage, for

25 instance through only one dog clutch provided with inclined end surfaces being provided, while for instance for the rest a normal change-over clutch with straight dogs is provided, which is suitably connected to a separate arrangement for facilitating the change of speeds. The present in -vention relates more particularly to the last named arrangement. This arrangement is for instance so constructed that in one operative direction, for instance when changing down from speed, it acts as a synchronizing coupling, while in the other operative direction, for instance when changing up from the lower to the higher speed, it acts as a braking device for the gear. The invention also pro- 40 videsfor a particularly suitable mode of operation. As the synchronizing coupling, a disc or cone coupling is preferably used, which is disposed at one end of the gear. This arrangement has the advantage that the coupling can be made 45 so large as to make a really suficient and effective synchronization possible. As on the other hand other synchronizing couplings besides the one referred to need not be provided, there will in this case be no difliculties as regards the dimensions of the gear. The invention provides the further advantage that the arrangement for facilitating the 0p-.

eration of the gear is actuated by the gear lever through transmission gear, while the coupling co- 55 acting with it, for instance a dog clutch, sliding wheels or the like, is moved by means of the gear lever without any interposed transmission gear. Owing tov this the synchronizing moment which serves for facilitating the change of speeds can be considerably increased, without however, 5 in spite of the increase in the effective operative motion necessitated thereby, the total operative motion becoming too great owingto the direct actuation of the dog clutch.- The arrangement is preferably made such that at a certain resistance in the device for facilitating the changeover, that is for instance after synchronization has been effected, this device becomes automatically disengaged during the further operative motion and the new speed can be thrown in.

In the accompanying drawings a constructional example of the invention is shown v Fig. 1 being a longitudinal sectionv through the gear,

Fig. 2 a cross-section on line A-B of Fig. 1, which shows the arrangement for facilitating the change in elevation,

Fig. 3 a cross-section on line C-D of Fig. 2,

Fig. 3a is a plan view of a detail.

Fig. 4 an elevation of the mechanism for actuating the front change-over coupling,

Fig. 5 shows the mechanism in Fig. 4 in a different position .of the parts.

Fig. 6 a two-speed gear withthe arrangement for facilitating the change-over operation shown diagrammatically.

In Fig. 1, a is the engine coupling shaft, 17 the Cardan shaft and c the lay shaft. On the shaft 11 is mounted loosely the, toothed wheel d1 which is in constant engagement with the toothed wheel d2 which is fixed on the lay shaft. The same applies to the pairs of toothed wheels el-r'efl and f1 and f2 the toothed'whe'el e1 being mounted so as to be capable of turning loosely between: the shafts a and b with respect to these shafts and the toothed wheel 11 being mounted loosely on the Garden shaft b while the toothed wheels e: and I: are fixed on the lay shaft like the toothed wheel 412. All these toothed wheels are preferably provided with inclined teeth so as to render them noiseless.

Between the toothed wheels di and e: and capable of. being alternately coupled with them is av change-over coupling g which is slidable on the engine coupling shaft. A further change-over coupling his provided between the toothed wheels c1 and f1, so as to be capable of being coupled with them. This coupling is mounted'o'n the Cardan shaft so as to be capable of sliding thereon but not of turning. It is lnade in the form 55 which is rotatably mounted on further slid E wheel of a sleeve and is provided with keyways for a 11 which can be brought into engagement with the toothed wheel is of the lay shaft.

For changing four selector bars 760, hi, hi, k: are provided which are operated from a common operating lever 10. The bar kc serves for putting into and out of operation by means of a fork 160' a reverse toothed 'wheel (not shown) \which is for instance to be brought into engagement simultaneously with the toothed wheels 11 and is. The bar In through the fork k1 effects the shifting of the toothed wheel 11, the bar It: serving for actuating the change-over coupling h by means of the fork 16: as well as the means for facilitating the gear changing operation, hereinafter described, and the bar It: serving for actuating the changeover coupling a through nism shown in detail in Figs. 4 and 5. f

The mechanism shown in Figs. 4 and 5 is constructed as follows: On the bar It: is secured a sleeve 163' provided with a'fork ka" which actuates a double-armed lever 11 pivoted in the gear casing in such a manner that it can be moved out of the position shown in Fig. 4 into the position shown in Fig. 5. 0n the lower end of the lever 11 is pivoted a bar I: which at its left hand end has a head 13 with a slot 14 in which on a bell crank 1m a shaft mo in the gear casing, the said stud being slidable in the slot 14 to a certain extent. On a stud m1" provided on the other arm attached onejend of a tension spring ms, the

engages a stud m1 provided other end of which is attached to a stud fits on I -on the shaft mo.

one arm of a second bellcrank me also rotatable of the bell crank ma, as the coupling member a shown in Fig. 1, engages sleeve having circumferentialiy bevelledteeth shown in Fig.

thespring ms is moment on the bell a. The moment um mi into the terminal After the 'toactedandtending or dogs in known manner for alternative enteeth or dogs on gagement with corresponding the toothed wheels dr and er.

1f the selector bar It: is moved to the right, thereby turning the lever li'into the position 5, then after a, certain amount of idle motion the stud m1 of the bell crank 1m comes into contact with the end of the slot which turns the bell ms to start with remains in the position shown in'Fig. 4, so that while first tensioned until the stud mi" into where the straight line connecting the centres of the studs Ms through the axis of the shaft mo, whereupon the spring contracts and rocks the bell .crank bell crank m1 dead centre position the m: produces a crank in: acting in theopposite-direction from that in which it has hitherin! torque m0]! however prevented the dogs of the coupling sleeve torque is reduced, however, e. g. by throttling the engine, the spring wheeler so that the bell crank out o! the position shown in Fig. 4 into that shown in Fig. 5. The bevellingoftheteethof the coupling sleeve 0 the speeds, as shown in Fig. 3,

two jaws 01, 0: in the the actuating mecharubbing contact with of the bell crank mi is A stud ma" on the other arm which is constructed as a The manner in which the various the bell crank m1 is turnthe-dead centreposition with respect to the stud-ma position shownin Fig. 5..

has moved beyond the toturnthebellcrankms. anticlockwise, such motion of the bellcrank be to start with by the.

coupling'sleeve out of engagement 7 enables the sleeve to be brought into engagement with the toothed wheel d1 with the minimum of noise the moment the speed of rotation of the wheeland the-coupling sleeve becomes equal.

In moving the coupling sleeve back into the position shown in Fig. 4 the cycle of operations is similar. For facilitating the operation of the change over coupling ha mechanism is provided which consists of a forked lever n which is pivoted below the Cardan shaft and embraces the shaft like a stirrup and which groove 0 of a sleeve 1) which is slidable on the toothed wheel h. At its two forked ends m and n: the 'lever is made T-shaped and is provided with recesses m and m respectively. In these recesses balls qi and q: engage, which are held in a bore of the T- shaped end its of the bar It. Under the action of a spring q: the balls are spread apart and forced into the recesses m and m.

The sleeve p is provided at one end with a collar p1, and at the other endwith a coupling bell n which supports the inner cone n of a;

cone coupling. The cone ncoacts with an outer cone 1': of a coupling bell s which is fixed on the ,Cardan shaft b. Between the jaws 01 and 02 and the bell p: a ball bearing t is interposed, so

that the jaws 01, 02 cause anengagement of the coupling 11 and r: to take placepractically' without friction. On'the' other hand, the .jaws O1, 02 of the non-rotary forked lever u make the collar in so as to conbrake when the change stitute a synchronizing over coupling h is moved to couple the wheeler r1, 1': is disposed I to the shaft b. The coupling in a separate rear chamber of the gear.

As the lay shaft terminates at the wall of the gear casing separating the rear chamber from the remainder of the casing anddoes not extend through this chamber, the coupling bells p; and s are not obstructed in any way by the lay shaft, the axis'of which if prolonged would intersect the coupling bells, so that the coupling bells can be made of comparatively large diameter and thereby of considerable efficiency.

gear'ratios are obtained is as follows:--

Assuming the parts to be in the neutral position shown in Fig. -1,- in order to change over to the first speed, the selector bar in is moved to the left, thereby bringing the toothed wheel 11 into engagement with v its remaining in the position shown in Fig. 1,

so that the drive takes place through the gear For changing over from the first to the second speed, the selector bar k1 is moved to the right to disengage the toothed wheel i1 from the wheel 'is and the bar It: is also moved to the right so as to move the change-over coupling it into engagement with the toothed wheel 11 and thereby flxthe said wheel to the shaft b at the same time the lever n is also carried to the right by the locking device, that is to say by the spring loaded balls qr and as which engage in the recesses m and m respectively, until the jaws Ol, 02 bring the cone coupling 11, 1'': into engagement by means of vthe ball bearing t. By this means the toothed wheel f1 which is in permanent engagement with the lay shaft and the coupling shaft :1 which is is'synchroniaed with it. On the pressure being inengages by means of is brought into frictional engagement with the wheelie, the bars kg and further to the right, the balls in, q: are forced out of the recessesm' and m and the synchronizing coupling is uncoupled from the selector bar. 5

The dogs of the sleeve h can now engage without shock in the corresponding dogs of the toothed wheel 11 and couple the latter with the Cardan shaft. The second speed is thus brought about through the gear members aeieac-fa hen-b. e

In order to change over from the second to the third speed, which in the construction shown is the direct drive, the selector bar It: is moved. to the left so as to bring the change-over coupling h out of engagement with the toothed wheel f1 and into engagement with the toothed wheel 21, the bars in and karemaining in the position shown in Fig. 1. In the middle position of the change-over coupling h and of the selector bar lag the balls qr and q: again engage in the recesses m and m. on the selector bar being displacedfurther to the left it therefore carries the lever 71 along with it again and presses the jaws 01 and 02 against the collar p1. Owing to the friction between the stationary jaws and the collar pi which turns with the toothed wheel ii, the

toothed wheel along with the lay shaft and the engine coupling shaft 4, which are in engagement with it, is braked to a certain degree. This braking action has the purpose of bringing the speeds of revolution of the parts It and e1 which are to be coupled more quickly into correspondence. In the second speed the toothed wheel e1 runs at a higher speed than the Cardan shaft b.

On the coupling h being disengaged from ii, the toothed wheel ii is released from the Cardan shaft, the coupling brake acting over the toothed wheel f1 and the lay shaft on the toothed wheel e1 which is thereby braked with respect to the Garden shaft or the change-over coupling h. Thus a more rapid and less noisy engagement of the dogs of h and ei becomes possible. The direct drive is by way of the gear members a-g-m-h-b.

For changing from the third to the fourth speed the coupling parts of e1 and h remain coupled, while the sleeve g is changed over in the manner above described with reference toFlg. 4 by means of the selector bar k: which for this purpose is moved to the right, the bars k1 and k2 remaining in the position they occupy for the third speed. This operation can be performed in a known manner without disengaging the ,en-

' gine coupling. The dogs of g and en remain in engagement even after the change-over of the spring controlled mechanism mF-ma-ma, as long as there is a driving torque between the engine and the vehicle. At the moment of a change-over in the drive (for instance through throttling the engine) the sleeve 9' will be changed over suddenly, the inclined dogs of the sleeve g and of the toothed wheel di repelling each other until both are running at'the same speed and enter The drive then takes place through the gear members 3. I, II, III, IV are the corresponding positions of the common gear lever is and R is the position for the reverse. As will be seen there are two positions for thiethird speed, according to whether the selector bar It: (the sleeve h) is being changed over" from the second speedor the selector bar It;

(sleeve g) from the fourth speed. This makes itpossible to cause the coupling brake actually to act only when changing from a lower speed into the third or direct speed, but not when changing over to the third or direct speed from the higher wheel e1 by shifting the selector bar It: to the right and engaged in the toothed wheel I; by shifting the selector bar its to the left, the synchronizing coupling r1, 1': being again operated. In contradistinction to the coupling brake p which correctly only becomes operative when changing from a lower to a higher speed, the synchronizing coupling is actuated both when changing up and when changing down, which isof considerable advantage, as it is immaterial for synchronization which of the two parts to be synchronized is the more rapidly or more slowly moving pne.

In changing from the second to the first speed the'change-over coupling h is again disengaged from the toothed wheel f1 by moving thebar k: to the neutral position shown'in Fig. 1 and in place thereof the sliding wheel 11 is brought into engagement with the toothed wheel i2 by moving the selector bar In to the left. In the same way a reverse speed wheel which is not shown can be brought into engagement by means of a selector bar k0, for instance simultaneously with the wheels i1 and i2. For these last changes a separate synchronizing device or the like is not provided, as it does not seem necessary in view of the practical conditions. In this case as well separate arrangements for facilitating the gear change remains in the neutral position.

To effect the change (fir from the second to the fourth speed, the bar kz is moved to the left and the bar It; to the right.

The path moved through by the operating lever 7:: when changing over from one speed to another is shown on the left-hand side of Fig. 3, the positions occupied by the lever k for the .various speeds being indicated by Roman numbers, while the position for the reverse is indicated by the letterR. The gate necessary for constraining the lever to travel along the required path is shown separately above the actual position occupied by it for the sake of clearness.

Fig. 6 shows a two-speed gear'which correspondsin principle to the gear shown in "Fig. 1, but in which the pairs of toothed wheels d1, 412

and ii, i: are omitted. Forthe restfthe reference letters are the same as in Fig. 1.

What I claim is:

1. In a change speed gear, a gear casing, comprising at least two chambers. a main driving gear shaft extending through both chambers ofthe'gear casing, a lay shaft extending substantially through only one of said chambers, gear sets for producing speed transmissions between the main driving shaft and the lay shaft arranged within the said chamber in which the lay shaft islocated and a synchronizing disc coupling on the main drivingshaft inside the chamber through which the lay shaft does not extend and having a diameter such that it is intersected by the prolongation of the axis of the lay shaft.

2. In a change speed gear, the combination of '40 701 and k: are moved to the right and the bar It:

a gearshaft, a pair of gear members and a change-over coupling for alternately placing said gear members into and out of driving engagement with the gearshaft, with change facilitating means comprising a sleeve on one of said gear members, said sleeve being axially displaceabie but not rotatable with respect to said gear member and having a coupling member rigidly connected to it, a coupling member on the gearshaft arranged to coact with the coupling member on the said sleeve for synchronizing the gear- 1 said operating means is moved into the one contogether through the trol position to couple up the gearshaft by the change-over coupling with the one gear member the coupling member on the sleeve is brought into engagement with the coupling memberon the gearshaf t substantially with the exclusion of fric-. tion between the control member and the coupling member on the sleeve and on the actuating means being moved into the other control position and thereby coupling up the gearshaft through the change-over coupling with the other gear member, the non-rotary control member is forced against the collar on the sleeve, friction is set up between it and the collar so as to produce a synchronizing braking action.

3. In a change speed gear, a driving'shaft, a

driven shaft, transmission gear members interposedbetween the driving and driven shafts for transmitting the motion of the former to the latter at one transmission ratio, further transmission gear members interposed between the driving and driven shafts for transmitting the motion of the former to the latter with a higher transmission ratio, change over coupling means for alternately coupling the driving and driven shafts first or second mentioned gear members, change facilitating means operatively connected to the change over coupling means and comprising a synchronizing coupling comprising two coupling members adapted to be brought into engagement with one another, one operatively connected to the driven shaft and the other to the driving shaft through the first mentioned transmission gear members for coupling the driving and driven shafts together on the change over coupling means'being operated to operatively connected to the the twoshafts to one couple the first-mentioned gear members to the driving and driven shafts and a synchronizing brake for retarding the motion of one of said shafts on the change-over coupling being operated to couple the driving and driven shafts together through the second-mentioned gear members. I

4. In a change speed gear, a driving shaft, a driven shaft, a change-over coupling for coupling another for producing one speed transmission, a synchronizing coupling comprising two coupling members adapted to be brought into engagement with one another, one driven shaft and the other to the driving shaft through the first mentioned transmission gear members for synchronizing the speeds of rotation of the two shafts prior to effect the to the change -over coupling being put into opera-- tion, an actuating bar for the change-over coupling and for the synchronizing coupling includ-' ing a lever linkage operatively connected to the synchronizing coupling so as to move said synchronizing coupling through a shorter distance. on the actuating bar being operated, than the and a yielding coupling device between the actuating bar and the synchronizing coupling for interrupting the operative connection between the actuating bar and the synchronizing couplingafter 7 coupling has been brought into operation by the actuating bar and before the further movement of the bar necessary change-over coupling.

5. In a change speed gear, driven shaft, a countershaft, pairs of constant mesh gear wheels, one wheel of each pair fixed on the countershaft, the other wheel of one pair rotatable on the driving shaft, the other wheel of a second pair rotatable on the driven shaft and the other wheel of a third pair rotatable for engagement of the the synchronizing a driving shaft, s

between the driving and driven shafts, a changeover claw-coupling on the between the gear wheel thereon and the gear wheel between the driving and driven shafts, a second change-over claw coupling on the driven shaft arranged between the gear wheel thereon and the gear wheel between the driving and driven shafts, a synchronizing device comprising coupling members rotatable respectively with the driven shaft and the wheel thereon for synchronizing the speed of rotation of said shaft and wheel and actuating means for simultaneously driving shaft arranged actuating the said synchronizing device and the change-over claw coupling on the driven shaft.

6. In a change speed gear, the combination as set forth in claim 3, with actuating means for the change-over coupling and operatlvely connected to the'synchronizing coupling and ,the SYl'iChIOfllZ'.

' ing brake so as to actuate the synchronizing coupling on the change-over coupling being actuated change from a higher to a lower speed and actuate. the synchronizing brake on. being actuated to effect the change from a lower to a higher speed.

'7. In a change speed gear, a driving shaft, a driven shaft, transmission gear members interposed between the driving and driven shaftsfor transmitting the motion of the former to the latter at one transmission ratio, further-transmission gear members interposed'between the driving and driven shafts for transmitting the motion of the former to the latter at another transmission ratio, change-over coupling means for alternately coupling the driving and driven shafts together through the first or second mentioned gear members, change facilitating means comprising a synchronizing coupling, one member of which is operatively connected up to the driven shaft and the other member is operatively connected up to the driving shaft and a braking device for retarding the rotary motion of the one shaft relatively "to the other and comprising a brake member connected to the shaft to be braked, so as to rotate with said shaft, and a non-rotary brake member adapted to be brought into braking contact with the first-. mentioned brake member, and a common actuating ;device connected up to the change-over coupling and the change facilitating means, so

2,090,510 members of the synchronizing coupling are brought into frictional contact withone another and prior to the driving and driven shafts being brought into drivingconnection with one another through the second mentioned gear members, the rotating member of the braking device is brought into frictional contact with the non-rotating brake member.

8. In a change speed gear, the combination as set forth in claim 7, in which the common actuating device comprises an actuating bar having an actuating fork for the change-over coupling means, a lever member having a long arm connected to the actuating bar and a short arm connected to the change facilitating means serv-' of a second pair rotatable on the driven shaft and the other wheel of a third pair rotatable between the driving and driven shafts, a changeover claw coupling on the driving shaft arranged between the gear wheel thereon and the gear wheel-between the driving and driven shafts, ac-

tuating means for said change-over claw coupling including a snap-over device, a second change-over claw coupling on the driven shaft arranged between the gear'wheel thereon and the gear wheel between the. driving and driven shafts, a synchronizing coupling device comprising coupling membersrotatable respectively with the driven shaft and the wheel thereon for synchronizing the speed of rotation of said shaft and wheel, a synchronizing .brakingdevice comprising a brake member rotatable with the wheel upon the driven shaft and a non-rotatable brake member arranged to co-operate with the rotatable rake member, actuating means for the change-.. over claw coupling on the driven shaft-operatively connected to said synchronizing coupling braking action.

device and synchronizing braking device so as to operate the synchronizing coupling device and the synchronizing braking device alternately, a

gear change control member movable to engage separately with the actuating means for the change-over coupling on the driving shaft and the actuating means for the change-over coupling on the driven shaft and guiding means for said gear change control member for permitting en- 7 gagement thereof with the actuating means for the change-over coupling on the driving shaft only when'the actuating means operatively connected to the rotatable brake member is in the position to operate the synchronizing braking device.

10. In a change speed gear, the combination of a gear-shaft, a pair of gear members and a change-over coupling for alternately placing said gear members into and out of drivingengagement with the gearshaft, with change facilitating means, comprising asleeve on one of said gear ,members, said sleeve being axially displaceable but not rotatable with respect to 'said gear member and having a coupling member rigidly connected .to it, a coupling member on the gear- .shaft arranged to coact with thecoupling member on the said sleeve for synchronizing the gearshaft with. the gear member having the sleeve I thereon, acollar rigidly connected to the sleeve,

a non-rotary control memberfor actuating the sleeve arranged between said collar and the coupling member on the sleeve, so as to bear on one side against the collar, and operating means for actuating in unison the change-over coupling and I the said non-rotary control member so that when the said-operating means is moved into the one control position to couple up the gearshaft by the change-over coupling with the one gear member the coupling member on the sleeve is brought into engagement with the coupling member on the gearshaft and onthe operating means being moved into the other control positionand thereby coupling up the gearshaft through the changeover coupling with the other gear member, the non-rotary control member is forced against the collar on the sleeve and friction is set up between it and the collar so as to produce a synchronizing 

